Display Device Flicker Prevention via Blank Period Voltage Control
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Solution Overview
Problem
Display devices experience flicker when display frequency changes, and existing methods either require frame memory or result in visually noticeable luminance differences, which are not ideal solutions.
Innovation Solution
A display device and driving method that manage grayscale data supply during active and blank periods, using different power voltages and switch control signals to maintain consistent luminance without the need for frame memory, by adjusting the lengths of blank periods and applying specific voltages during these periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If different data voltages are used for the same grayscale when display frequency is changed, then flicker can be reduced, but luminance difference of at least one frame is visually recognized by user
Solution Approach 1:
The patent changes the voltage parameter applied to pixels based on display frequency detection. When low frequency is detected, a first voltage (different from the normal first power voltage) is applied during blank periods, while maintaining the same grayscale data voltage during active periods. This voltage parameter change compensates for flicker without causing luminance differences during display.
Solution Approach 2:
The patent applies a different voltage during the blank period before the active display period. This preliminary voltage adjustment prepares the pixel state in advance, ensuring that when the active period begins, the pixel will maintain consistent luminance across different display frequencies without visual artifacts.
2Reliability
If image is displayed with a delay by one frame to prevent flicker, then flicker is reduced, but a separate frame memory is required
Solution Approach 1:
The patent extracts and removes the frame memory component from the system. Instead of using frame memory to delay image display, the invention uses voltage control during blank periods to prevent flicker, thereby eliminating the need for separate frame memory while maintaining flicker prevention functionality.
Solution Approach 2:
The patent introduces a voltage control mechanism as an intermediary between the display frequency detection and the pixel output. This intermediary voltage adjustment during blank periods serves as the mediating element that prevents flicker without requiring frame memory, replacing the traditional memory-based approach with a voltage-based control approach.
3Measurement precision
If blank period is extended to allow frequency detection, then display frequency can be detected, but active display time is reduced
Solution Approach 1:
The patent applies voltage control only during the blank period rather than throughout the entire frame period. This partial action approach allows frequency detection and compensation during blank periods without affecting the active display time, maximizing the use of available time resources.
Solution Approach 2:
The patent uses periodic voltage adjustments during blank periods that occur regularly between active display periods. This periodic action during blank periods enables continuous frequency detection and adaptation without interrupting the active display time, maintaining both detection capability and display productivity.
Data Source
AI summary
A display device of the present inventive concept includes a processor supplying grayscale data in active periods of frame periods and stopping supply of the grayscale data in blank periods of the frame periods; a switch controller generating a first switch control signal when a blank period is longer than a predetermined period, and generating a second switch control signal when the blank period ends; a power supply supplying a voltage different from a first power voltage to a first power line when the first switch control signal is received and supplying the first power voltage to the first power line when the second switch control signal is received; and pixels commonly connected to the first power line.